Permanent magnet



Patented Apr. 7, 1936 UNITED STATES PATENT OFFICE 2,036,281 PERMANENT MAGNET Werner Ktister, Dortmund, Germany, assignor, by mesne assignments, to Deutsche Edclstahlwerke Algtiengesellschaft, Crefeld, Germany N Drawing. Applicati on July In Germany July 25, 1931 22, 1932, Serial 1 Claim. (Cl. 148-31) to a process for the of ferromagnetic alloys.

The present invention constitutes a special application of the process hardening and containing '7 to 30% of at least one metal selected from the group tungsten and molybdenum together with 0.5 to 20% of cobalt, the alloy comprising substantially all iron.

Thesealloys receive their good properties, if they are first quenched from a temperature lying between about 900? C. and the melting point and then tempered at a temperature below the quenching temperature, preferably between about 500 and 800 C. Said treatment corre- During the tempering a second type of crystals is separating out, namely that type of crystals which are dissolved by anhealing.

The diiTcrent metallographic basis of the noncarbon or low-carbon steels of the present invention,

especially in magnets of complicated form, or in the provision of fine bores, nets made from the alloys tion can, on the contrary, be roughly shaped,

whereas, with the old magnet steels, lower values are obtained in cooling than in heating.

The following examples will serve to illustrate the invention:

Example 1 An alloy of 9.8% of cobalt, 18.2% of tungsten, 1.4% of vanadium and 0.04% of carbon gave, after quenching from 1275 C., a coercive force of 4 Gauss, a remanence of 4200 Gauss and a Brinell hardness value 320. After tempering for 30 minutes at 750 C., the coercive force became 108 Gauss, the remanence 11750 Gauss and the hardness 550.

Example 2 An alloy with 5.2% of cobalt, 15.6% or molybdenum, 0.6% of vanadium and 0.04% of carbon gave, after quenching from 1100 C. and tempercaused by precipitation hardening of such alloy. 15

WERNER KGSTER. 

